The transformation of steroids by microorganisms has been widely studied and documented. Apparently, the earliest such work was by Mamoli and Vercellone in 1937, Ber. 70, 470 and Ber. 70, 2079. They disclosed the reduction of 17-ketosteroids to 17.beta.-hydroxysteroids by fermenting yeast. More recently, Peterson and Murray diclosed the 11.alpha.-hydroxylation of progesterone with the fungus Rhizopus nigricans; see, U.S. Pat. No. 2,602,769 (1952). Also recently, Kraychy et al. in U.S. Pat. No. 3,684,657 (1972) discloses the selective microbiological degradation of steroidal 17-alkyls by fermenting a steroid containing at least 8 carbons in the 17-alkyl side chain with Mycobacterium sp. NRRL B-3683 to prepare androst-4-ene-3,17-dione, androst-1,4-diene-3,17-dione, and 20.alpha.-hydroxymethyl-pregna-1,4-dien-3-one. Even more recently, Marsheck et al. in U.S. Pat. No. 3,759,791 (1973) disclose the selective microbiological preparation of androst-4-ene-3,17-dione by fermenting a steroid of the cholestane or stigmastane series containing at least 8 carbons in the 17-alkyl side chair with Mycobacterium sp. NRRL B-3805.
Also pertinent in the background of the subject invention is the article by Schubert, K., Bohme, K-H., and Horhold, C. entitled "Formation of low molecular degradation products from progesterone by microorganisms," Steroids 4, 581-586 (1964). These authors described the formation of tricyclic intermediates during the degradation of progesterone by Mycobacterium smegmatis.
The culture of the subject invention process, Mycobacterium fortuitum NRRL B-8129 is disclosed in pending applications Ser. Nos. 632,635, filed on Nov. 17, 1975, now U.S. Pat. No. 4,039,381, and 745,113 filed on Nov. 26, 1976, now U.S. Pat. No. 4,062,729. The process conditions disclosed in Ser. Nos. 632,635 and 745,113 are not conducive to the optimal production of compound I of the subject application.